Feed leg control for stoping drills



Patented Oct. 13, I942 FEED LEG CONTROL FOR STOPI NG DRILLS MatthewOFarrell, Detroit, Mich., assignor to Chicago Pneumatic Tool Compa ny,New York,

N. Y., a corporation of New Jersey Application September 20, 1941,Serial No. 4l1,618

This invention relates to control valves for pressure fluid operatedtools and like devices. ore particularly it relates to valve assembliesof the kind used to control feed leg pressures during drilling,independently of the throttle valve.

Such valve assemblies are customarily mounted in the rotation handle ofthe drill and provide an exhaust port control valve, an actuatingplunger reciprocable within the handle and a finger piece or buttonoutside the handle secured to the valve plunger. Prior art structuresare comprised of a plurality of. unconnected subassemblies making itimpossible to handle the valve as a single unit in. inserting it in thetool and removing it therefrom. Further, it heretofore has beenconsidered necessary that the finger piece or button, by which the valveis controlled, be pinned or otherwise detachably secured to the valveplunger, or that the bushing in which the valve plunger reciprocates beof split construction. The cost of the conventional valve structureaccordingly is greater than one in which the finger piece may be madeintegral with the valve plunger and the valve bushing made in a singlepiece. The latter construction has the additional advantages of greatersturdiness and reliability.

The object of this invention is to overcome the above-reciteddisadvantages inherent in feed leg release valves of the prior art.

In carrying out this object there has been provided a valve structure ofsimple and rugged construction which may be completely assembled priorto its insertion in the tool. The valve plunger and finger piece areformed integrally, the plunger reciprocating within a one-piececylindrical bushing and having a p ppet valve reciprocably mountedthereon and held against axial relative movement by a spring assemblyremovably -secured in a novel to the inner end of the plunger. The valveplunger and-poppet valve thus may be moved as a unit with respect to thevalve bushing, the valve being adapted for engagement with the inner end01' the bushing to control the flow of pressure fluid therethrough.

Other objects and structural details of the invention will be apparentfrom the following description when'read in conjunction with theaccompanying drawing, wherein:

Fig. 1 is a fragmentary view, partly in longitudinal section and partlyin side elevation, of

in rock drills of the stoper type manner 5 Claims. (Cl. 251--137)ring-shaped a stoning drill embodying the present invention.

appearance.

some parts being shown diagrammatically for the sake of clearness;

Fig. 2 is a fragmentary view of the rotation handle, showing the feedleg control valve inlongitudinal section; and I Fig. 3 is a detail viewof a slotted washer adapted to be mounted on a reduced portion of thevalve plunger end of the valve spring.

Figs. 2 and 3 are on a larger scale than Fig. 1. As shown in Fig. 1,

comprises a cylindrical head block III, the oppomounting for the motorelements which include a reciprocable hammer piston in splinedengagement with a rifle'bar IS. .A head 20 or the rifle bar abutsagainst the head block l0 and cooperates with an encircling pawl andratchet mechanism IE to effect step-by-step rotation of the rifle barand hammer piston. A distributing valve assembly I1 is held within theinner end of the cylinder I I by the rifle bar head 20 the head block Ithrough a port 1 8 in the rotation ratchet, and is directed by anautomatic action of the valve to alternate ends of the hammer piston.The pressure fluid is supplied to tending into a transverse bore 2| inthe head block HI. Also positioned in the bore 2| is a thereby toinitiate and terminate the different stages-of tool operation.

The rearwardly extending cylinder l2 constitutes a body is advancedupwardly and forwardlytoward and into the wall or ceiling oi the mine.While drilling the feed leg maintains a steady pressure on the tool,urging it constantly into engagement with the work so that deepening ofthe drill to serve as a seat for one the stoper type rock drill Thefront cylinder ll provides a;

hole is reflectcd'in a'corresponding lengthening of the 'feed leg. Alaterally extending handle '25 is provided for steadying the tool duringits operation, and may 'be used to efiect manual rotation thereof. Therotation handle is removably secured to the tool, being passed through atransverse bore above the throttle valve and held therein by a lock nut26 in threaded engagement with the projecting inner end of the handle.

The compressed air passages'leading from inlet bore2l to the feedcylinder I2 are indicated diagramatically inFig. 1. 'As there shown, apassage 21, controlled -by"-throttle valve 22, is connected throughalongitudinal passage 28 in the rotation handle with a passage '23opening into the feed cylinder 12 aboveithepiston '23. Thus, when thethrottle valve is'set in a position to-admit pressure fluid to thepassage 21 and thence to the feedfleg, theipressure established withinthe feed .cylinder'is'extended alsoto the longitudinal bore 28inthe=rotation handle 25. This disposition of 'fiuidsupply-passages makespossible an auxiliary control of the air pressure inthefeedleg byvariably reducing the pressure within the rotation handle. Such pressurecontrol is accomplished by connecting thepassage 28 to an exhaust portand selectively opening and closing the exhaust port as the character ofthe work shall require. During normal :drilling operations the exhaustport is closed. However, when the drill steel en- -cunterseither a softor an unusually hard fortionsthroughoutoperation ofthe tool. Thepressure within the 'feed leg is also reduced in this manner whenlowering the machine from the work attheen'd of a drilling operation.Preferably the auxiliary control of feed leg pressures is effectedthrough an exhaust port control valve located for convenientmanipulation in the rear of the rotation handle.

The air feed control valve is the subject of this invention, and, asshown in Figs. 1 and 2, is comprised of a structure 3| positioned withina counterbore or recess 30 at the outer end of handle bore 28. Theexhaust port controlled by the valve structure isindicated at 32, and isseen to connect the eounterbore 30 to an open-chamber 33inthe laterallyextending grip portion of the rotation handle.

The principal elements of the assembly 3! are a-cylindrical bushing 34,a plunger '35 extending through the bushing, and a valve 36 reciprocablymounted on the projecting inner end of the plunger and adapted forengagement with the :inner end of the bushing. The valve bushing has ascrew threaded engagement with the wall :oi bore 30 and is formed withahead 31 shaped to receive a wrench andefiective to limit movement ofthe bushing into the eounterbore. The

internal formation of the bushing 34 provides a a longitudinal bore .38in which the shank of plunger-35 1185 a sliding 'flt. At the front ofbore 38 1a eounterbore 38 is formed receiving a head 4| plunger-35.=A=coil spring is confined within the eounterbore 39 by the head 4| andurges the plunger 35 outward or toward the right as viewed in thedrawing. At the inner end of bore 38a eounterbore 43 is formed whichcommunicates through a series of ports 44 with an annular groove 45 inthe outer surface of the bushing 34. The groove 45 is adapted toregister with the exhaust port 32 and when so positioned connects thec;unterbore 43 to atmosphere.

Communication between the eounterbore 43 and the rotation handle bores28 and 30 is controlled by the valve 36 which has a beveled surface 46complementing a similar surface on the inner end of the bushing 34. Thevalve 36 has the shape of a ring encircling a reduced stem-like portionof the plunger 35. A coil spring 4'! surrounds the plunger below thevalve 36, being arranged between the valve and a spring base comprisinga washer 48 removably attached to the inner end of the plunger. By thepressure of spri g 41 the valve 36 is urged into engagement wi. alimiting shoulder 49 on the plunger 35. Thus, the plunger 35, valve 36,spring 41 and washer 48 constitute a unitary assembly pressed outward bythe spring 42 and limited in such movement by engagement of the valvering with the seating surface at the inner end of bushing 34. Thelimiting shoulder 49, on plunger 35, is also formed as an annular valveseat and prevents seepage of pressure fluid around the inner peripheryof the valve 36. Normally, therefore, the counterbore 43 in bushing 34is closed and the escape of pressure fluid therethrough prevented. If,however, the plunger is pressed inward the entire assembly of which thevalve 36 is a part moves inward, causing the valve to move out of seatedposition with respect to bushing 34, and thereby opento exhaust theports and passages leading to the feed cylinder Ill. The head of valveplunger 35 extends outside the bushing 34 andhas a portion 5| ofenlarged diameter on its outer end, serving as a push button and as ameans for limiting inward movement of the valve assembly.

Since the entire plunger assembly moves as a unit, the spring 41 has nofunction other than to urge valve 36 so firmly against shoulder 49 thatfor mechanical purposes the valve and shoulder may be consideredintegral. The spring 41 therefore can be made considerably stiffer thanspring 42 which must be so calibrated that it can be compressed easilyby thumb pressure. As shown in Figs, 1 and 3, the spring base washer 48ms a c shape being slotted in order that it may be mounted on theplunger 35 by a lateral movement causing it to embrace a peripheralcut-out portion 52 (Fig. 2) in the stem of the plung r. The cut-outportion 52 defines an annular flange 53 at the inner extremity of theplunger, against which the washer 48 is pressed by spring 41. The innerperiphery of C washer 48 has twc diameters, the portion of largerdiameter encompassing flange 53 for more than half its periphery toprevent the washer from slipping laterally of! the plunger, and theportion of smaller diameter having a sliding fit within cut-out portion52 to prevent removal of the washer by an axial motion.

Thevalve structure 3| is assembled by placing the-spring 42 upon theshank of plunger 35 and then passing the plunger through the bushing 34,the spring 42 being thereby confined within the eounterbore 39. Thevalve 36 then is slipped over the flange 53 and moved toward the shoul-(ler 49 on the plunger. The spring 41 follows the valve 36 and iscompressed sufficiently to permit O washer 48 to be placed-within theperipheral cut-out 52'between spring" and flange 53; When released, thespring 41 urges washer 48 against theflange 53 and thejvalve 36againstvalve seat shoulder 49. The spring 42 acting on the head 4| oftheplunger presses ,the plunger and associated elements outward causingthe valve 36 to engagethe inner end of the bushing 34, the several partsthus assuming normally the positions here illustrated. The completedassembly, may be screwed into the counterbore 30 until the bushing head31 is seated against-the i rear of the rotation handle. ,In the fullyinserted position of the bushing the peripheral groove 45 therein isaligned with exhaust port 32.

What is claimed is:

1. In a pressure fluid operated tool or like device having a recesssupplied constantly with pressure fluid and a pressure fluid passagewayopposite or inner and outer ends of said bushing,

a series of radial ports in said'bushing communicating the inner of saidcounterbores with the said pressure fluid passageway, a plunger slidablymounted in the longitudinal bore in said bushing and having inner andouter ends pro jecting beyond the respective ends of said bush-' ing, ahead on the outer end of said plunger extending into the outer one ofthe counterbores in said bushing, acoil spring confined in said outercounterbore by the head of said plunger and acting to press said plungeroutward, a ringshaped valve reciprocably mounted on the inner end ofsaid plunger, a slotted washer embracing the inner end of said plunger,acoil spring interposed between said valve and said washer, abutmentportions on said plunger limiting move-- ment of said valve andsaid'washerby said spring, and complementary tapered seating surfaces onone of said abutment portions and the inner periphery of said valveforming a valvular connection preventing the escape of pressure fluidaround the inner periphery of said valve, the outer periphery of saidvalve being adapted for engagement with the inner end of said bushing toclose and open the inner counterbore in said bushing and thereby cut offand establish communication between said recess and said pressure fluidpassageway, and the assembly comprising said plunger and said valvebeing reciprocable as a unit within said bushing to seat and unseat saidvalve with respect to said bushing.

2. In a pressure fluid operated tool or like device having a recesssupplied constantly with pressure fluid and a pressure fluid passagewayleading from said recess, a manually operated valve structure positionedin said recess to control the flow of pressure fluid through saidpassageway, said structure being inserted in said recess andremovedthereirom as a unit and comprising a cylindrical bushing theouter periphery of which is threaded for engagement with a complementarysurface in said recess, a longitudinal bore in said bushing,counterbores in the opposite or inner and outer ends of said bushing, a

series of radial ports in said bushing communiouter ably mounted in thelongitudinal bore'in said bushing and having inner and outer endsprojecting beyond the respective ends of said bushing, a head on the.outer end of said plunger extending into the outer one of theeounterbores in said bushing, a first coil spring confined in said andacting to press said plunger outward, a ringshapedyalve 'reciprocablymounted on the inner end ofsaid plunger, a slotted washer embracing theinner end of said plunger, a second coil spring,

interposed between said valve and said washer, abutment portions on saidplunger limiting movement of said valve and said washer by said secondspring, and complementary tapered seating surfaces on one of saidabutment portions and said, valve forming a valvular connectionpreventing the escape or pressure fluid around .head of said plunger tounseat said valve with respect to said bushing and permit the flow ofpressure fluid from said recess through said inner counterbore andthence to said pressure fluid passageway.

3. A valve structure, comprising a cylindrical bushing, a longitudinalbore in said bushing, a plunger extending through said longitudinal boreand adapted for manually controlled reciprocable movement therein, saidplunger having first and second ends extending outside correspondingends of saidbushing, a counterbore in the first end of said bushingforming a fluid passageway through said shaped valve reciprocablyplunger outside the first spring base removably attached to the firstend of said plunger, a coil spring surrounding said plunger andinterposed between said spring base structure, a ringmounted on said andsaid valve thereby to urge said valve toward the adjacent end of saidbushing, said valve being adapted to seat against said bushing toprevent the flow of pressure fluid to and from said counterbore aroundthe outer periphery of said valve, and a valve seat on said plungerengaged by said valve to prevent the flow of pressure fluid to and fromsaid counterbore around the inner periphcry of said valve, the assemblycomprising said plungensaid valve and said spring base beingreciprocable as a unit relatively to said cylindrical bushing to seatand unseat said valve with respect thereto.

4. A valve structure, comprising a cylindrical bushing, a plunger withinsaid bushing and formed with a finger piece projecting from one ,end ofsaid bushing and a stem projecting from counterbore by the head of saidplunger 4 part of a pressure end of said bushing, a

plunger between said prising said plunger, said valve, said spring andsaid spring base being reciprocable as a unit relatively to said bushingto seat and unseat said valve with respect to the adjacent end of saidbushing, thereby to control the flow of pressure fluid into said bushingaround the outer periphery of said valve.

5. A valve assembly, comprising a reciprocable plunger having anintegrally formed finger piece at one end and a stem portion at theopposite end, ,a ring-shaped valve reciprocably mounted on .the stemportion of said plunger, a shoulder on said plunger intermediate saidstem portion and said finger piece for limiting movement of said valvein one direction, said shoulder acting as a seat for said valve toprevent the flow of pressure fluid around the inner periphery thereof, aperipheral cut-out portion in the stem of said plunger defining anannular flange thereon, a slotted washer embracing said cut-out portionand positioned between said valve and said annular flange, and a coilspring interposed between said washer and said valve pressing said valveinto engagement with said shoulder and said washer into engagement withsaid annular flange.

MATTHEW OFARRELL.

